Signal device for filters



y 2, 1953 H. E. MARVEL 2,638,581

SIGNAL DEVICE FOR FILTERS Filed June 21, 1950 3 Sheets-Sheet 1 III II 111! HARVEY E. MeRvEL INVENTOR.

B 1 Mm 01/76 ATTORNEY y 1953 H. E. MARVEL 2,638,581

SIGNAL DEVICE FOR FILTERS Filed June 21, 1950 3 Sheets-Sheet 2 HHRvEY ENAMEL INVENTOR.

BY%VI4/W RTTORNEY May 12, 1953 H. E. MARVEL SIGNAL DEVICE FOR FILTERS 3 Sheets-Sheet 3 Filed June 21, 1950 H HEVEY E. M HRVE L INVENTOR.

ATTORNEY Patented May 12, 1953 Harvey E. Marvel, Fort Wayne, Ind., assignor. to The Briggs Filtration Company, Washington, D. C., a corporation of Maryland Application June 2;, 1950, Serial No. 169,342

10 Claims. (01. 340-240) 1 This invention relates to a signal for filters. More specifically, it relates to a signal which may be attached to a filter of the replaceable cartridge type which will indicate when the cartridge has been rendered unserviceable and requires replacing. I I

It is an object of the invention to provide a signal which is inexpensive, simple and easy to install.

Another object of the invention is to provide a signal which is positive in operation.

A further object of the invention is to provide a transparent signal tube in which the level of liquid indicates the state of operability of the cartridge.

Yet another object of the invention is to provide a transparent signal device having an indicator section, in which dirty liquid does not contact the indicator section.

Another object of the invention is to provide means which will retain the reading on the signal even when the signal operating pressure has been dissipated. v

A further object of the invention isto provide a remote indication of'the signal.

These and other objects will become apparent from a study of this specification and the drawings which are attached hereto, made a, part hereof, and in which:

Figure 1 is a vertical sectional view of a filter with a signal attached and showing valve means for retaining the indication after the pressure has been dissipated.

Figure 2 is a vertical sectional view of a modified form of signal in which a fluid other than the fiuid being filtered is used as an. indicator. I

Figure 3 is a vertical sectional view of a modified form of signal similar to that of Figure 2, but provided with remote indicating means.

Referring to Figure l, the numeral l represents a filter bowl having an inlet 3, an outlet 5 and a cap I. A filter cartridge 9 is mounted in the path of the fluid passing from the'inlet to the outlet. I

A by-pass passage I I and a spring loaded valve I3 are provided in a stem I5 to provide a path for unfiltered liquid around the cartridge when it is plugged. The stem screws into post I6 which is a part of the filter bowl.

The passage IT in the stem l5 communicates with passage l I and with a transparent tube I9 which is sealingly mounted on a gasket 2| in a socket 23 formed in the end of the stem. The upper end of the tube is sealed by a plug 25.

1 The gasket ZI is provided witha valve seatzl 5} outside of thebag.

2 a adapted to receive a downwardly closing ball valve 29.

Operation When a new cartridge is installed, the stem I5 is unscrewed from the post I6. At this time the valve ball 29 maybe lifted to drain the signal tube I9 and restore the pressure therein to atmospheric. When the filter is reassembled, with a new filter element and the fluid, under pressure, flows tothe filter, liquid from the filter will fill the bowl and rise to a normal height in the tube I9, which may be scored or otherwise marked to indicate a normal level.

As the filter becomes plugged, the inlet pressure rises and compresses the air in the tube above the liquid and the liquid level rises in the tube. When a pressure equivalent to that at which the by-pass valve I3 opens is reached, the level in tube l9 will have reached a maximum, which may be indicated by a score or other mark R which indicates that the cartridge should be replaced.

' The ball 29 is seated to prevent liquid from flowing from the tube whenever the pressure is released on the filter so that an indication is retained on the indicator at all times.

First modified form.

The form shown in Figure 2 comprises a filter including a bowl 3| having an inlet 33, an outlet 35 and a cap 31. A filter cartridge 39 is mounted in the path of fluid passing from the inlet to the outlet.

The cap is held in sealing relation on the bowl by a stem 4| which is screwed in a post 43 which forms part of the bowl.

The upper end of the stem is provided with a socket 44 into which a nipple 45 is fitted. A transparent tube 41 is fitted on the nipple and has an indicating bore 49, a reservoir bore 51 and a counterbore 53.

A tubular bag or diaphragm 55 of rubber or other extensible material has a radial flange 5'! at its mouth which is held against the nipple by a collar 59 and the shoulder formed by the counterbore. v

A channel 6| in the stem and nipple communicates with the inlet and with the interior of the bag.

The exterior of the tube may be threaded at 63 to receive a, ring nut 65 which may be set at will. An indicating liquid 61 which may be mercury, colored glycerine, colored alcohol or other low freezing point liquid is disposed in the reservoir Operation 49. The air trapped in the bore is compressed by the liquid.

When the pressure in the filter reaches :a predetermined amount, at which the cartridge should be replaced, the liquid level ,inbore 59' will'halie, attained a corresponding predetermined level which may be indicated by the position of the ring nut on the tube ll.

risen to the ring nut level in bore 49, that the filter cartridge. should "be changed. The observation must, of course, be made-when the filter is under operating pressure because the indicating liquid would otherwise be in the reservoir and not inboreii Second; modification A-local and remote indicating signal device "is disclosed in Figure-3,111 which the. filter com prisesa bowl ,ll'having an inlet l3 and an outlet L 89 and a threaded counterbore $3 which resolves a bushing, 95. The latter has an internal, threaded socket to which receives a nipple: 85. Therbushing and nipple have centralperforations 9.8 and Hill respectively, which comrnunicatewith the channel 5 B2 .in the stem.

An extensibleba or diaphragm 95', of rubber or other elastic material extends through the opening 98 and base flange Bl'which is compressed-between the bushing and nippleto form agseal across the bottom of the reservoir.

The bag confines, in the reservoir bore, .a-liquid NH such asmercury, colored alcohol or colored glycerine or any other suitable material which is electricallyconductive or is, made sobyadding acid or. other ionizedmateriah The tube is open at its upper end and is threads ed at we to receive a cap I05 in, which an electrode I0? is sealed. The electrode exten-dsldow-n into the bore 89 to a level which will be occupied by v the indicating liquid when--the.press1 1ne-.-in the filter indicates that it is plugged.

The electrode isconnected by a.-, wire lll'lfito; onesidevof a signal lamp I09,- the-other,side of Whichisconnected by wire i II to a battery-J is. .The battery; is grounded at 1 i5 and the filter, is grounded at I ll.

Indicia may bemarked on oruattachedto the tube, .ii,desired,, although this is not necessary since the electrode Illi serves as the maximum height indicator.

Operation As stated above, the reservoir 9], is filiediznret erably. to the bottomotbore 8.9, ,;wi-th:a conduc: tive liquid which is also preferably; coloremgso The operator willfthus be apprised, on seeing that the indicator. has.

that it will serve as a visible indicator in the transparent tube.

When normal pressure is applied to the filter, the indicating liquid will rise in the bore 89, compressing the air therein.

When the filter becomes plugged, the pressure rises further and forces the liquid into contact with the electrode I01 which closes acircuit from the -battery through the'lamp Hi5) to light the lamp and signal to the operator that the cartridge requires replacement.

.Therlampmay, of course, be located at a point remote from the filter.

Itis obvious thatevarious changes may be made .inthe-form,structure and arrangement of parts without zdepartingfrom the spirit of the inven- 121011.. Accordingly applicant does not desire to be limited to the specific embodiment disclosed herein primarily for purposes of illustration; but instead, he desires protection falling fairly within thescope; of the appendedv claims'i What. 1 claim ,to be; new andvdesire-to; protect by Letters: Patent. ,of' the United; States is 1 In; aq-filterzhaving an inlet. and-an outlet, the m g a r n upright, transparent tube having its upper end closed, meansndefining a single conduitrconnectingw the lower end of the tube-with: the filter inlet and a gas disposed in the upper portion of the tube.

In asfilter. havinganinlet and an outlet, the combination ot-anmpwardly extending, transpare ent ztuberhavinggits upper; end-iclcsed, means, de fininea sinslnconduitconnecting the lower.- end of the tubei-Withrthe ,filterin-let,"az diaphragnr disposed in sealing relation across the tuloe,: a; gas .confinedgmthetopz portiomotithe'tube; an indicator liquid idisposediin, the-tube above the diaphragm and-level; indicatingimeans disposedradjacent the upper end otthe tube;

3. In a,- filter-harms aricase provided :with an inletiand an outletlastem attachedato the case andihavine azsinsle conduit thereinxcommunicat ing with the inlet, an upwardly directedtube soclcet. formed @zongthe stem',1 a: transparent: tube having a closedandcan'rcpeniendeand having its open end mounted in theisocketzsothat the-tube .extendsy-upwardl wield-able diaphragm mounted ransverselynofzthe tube; said tubehaving a large bore disposed adjacent: the diaphragm, Which'communicates; withraf-smallbore disposed adjacent the ;uppen;,end..-ofwthe tube, a; gas disposed in the upper cndaotthentube and an indicator liquid disposed in theiarge bore 4; In; 31:,fi'1bfl1 having; an. inlet: and an: outlet, the combination of an;uprightrytransparent tube avme: its 1 upper end 1c1osecl;.1.means defining .a single conduit?connectingwthealower end of the tube with the filter; inlet; a .gas disposed in the upper portionof the tube andeaxcheck :valvedisposedadiacent the. conduit; an.d1closing,.outwardly of, the tube ta-prevent :fiuid escaping: therefrom. '5. ma filter.-having aucase provided with an mletand "an outletca; stem ;attached to. the case having a single conduit therein communicating withgtheinlet an: upwardly directed tube socket formedslon-pthestem', .a combined valveseat and gasketofresilientmaterialdisposedzinthesocket; a transparentwtube .having a closed and an open end and having its openendzmounted "inisaid socketsi-nasealingrelation withzsaid-gasket sothat theatube-sextends upwardly, ages idiSDQSEd. in; the tubera-nclqa check valvein the-tube and cooperatin ithi-z said seat. to. prevent the L flowofv fluid iromtheitubel.

Y 6.; lnaefilter-nhaving an inietiandan zontletrthe combination of an upwardly extending, transparent tube having its upper end closed and its lower end open, a reservoir formed in the tube intermediate its ends, a resilient bag extending into said reservoir, means for sealing the bag in the tube to close oiithe reservoir, a liquid disposed in the reservoir and a gas disposed in the upper portion of the tube and means for applying pressure from the inlet of the filter to the bag.

7. In a filter having an inlet and an outlet, the combination of an upwardly extending, transparent tube having its upper end closed and its lower end open, a reservoir formed in the tube intermediate its ends, a counterbore formed in the lower portion of the reservoir, a resilient bag extending into said reservoir and having a flange seated in the counterbore, means for sealing the flange against the tube to close 011 the reservoir, a liquid disposed in the reservoir and a gas disposed in the upper portion of the tube and means for applying pressure from the inlet of the filter to the bag.

8. In a filter having an inlet and an outlet, the combination of an upwardly extending, transparent tube having its upper end closed, means defining a single conduit connecting the lower end of the tube with the filter inlet, a diapragm disposed in sealing relation across the tube, a gas confined in the top portion of the tube, an electrode extending into the tube adjacent the upper end thereof, an electric signal means connected with the electrode, a current conductive liquid disposed in the tube above the diaphragm and a source of electric energy connected to said signal means.

9. In a filter having an inlet and an outlet, the combination of an upwardly extending tube of electrical insulating material, said tube having a bore at the upper end, an intermediate reservoir and a counterbore at the lower end, a bushing of current conducting material sealed in said counterbore and having a perforation therein, an extensible bag mounted in the perforation so as to extend into the reservoir, means for sealing the bag against the bushing, means for connecting said tube to the filter with the bag in communication with the filter inlet, a gas confined in the upper portion of the tube, an electrically conductive liquid in the reservoir and an electrode sealedly mounted in the tube and extending into the upper portion of the tube.

10. In a filter having an inlet and an outlet, the combination of an upwardly extending tube of electrical insulating material, said tube having a bore at the upper end, an intermediate reservoir and a counterbore at the lower end, a bushing of current conducting material sealed in said counterbore and having a perforation therein, an extensible bag mounted in the perforation so as to extend into the reservoir, means for sealing the bag against the bushing, means for connecting said tube to the filter with the bag in communication with the filter inlet, a gas confined in the upper portion of the tube, an electrically conductive liquid in the reservoir and an electrode sealedly mounted in the tube and extending into the upper portion of the tube, a current responsive signal and a source of current connected with said electrode and the liquid in said reservoir.

HARVEY E. MARVEL.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,411,802 Mosher Apr. 4, 1922 1,685,211 Beck Sept. 25, 1928 2,145,304 Hill Jan. 31, 1939 2,294,330 Clark Aug. 25, 1942 2,328,131 Eisler Aug. 31, 1943 2,348,651 Schelly May 9, 1944 2,458,086 MacMillan Jan. 4, 1949 FOREIGN PATENTS Number Country Date 471,732 Germany Feb. 18, 1929 

